Flame jet burner construction



June 4, 1968 w. B. HORTON T AL 3,386,475

FLAME JET BURNER CONSTRUCTION Filed March 25, 1966 United States Patent FLAME JET BURNER CONSTRUCTION William B. Horton, Concord, Mass., and Ernest Marshall Fitzgerald, Norwich, Vt., assignors to H. E. Fletcher Co., West Chelmsford, Mass., a

corporation of Massachusetts Filed Mar. 25, 1966, Ser. No. 541,913 6 Claims. (Cl. 431-158) ABSTRACT OF THE DISCLOSURE A flame jet burner having a combustion chamber for burning fuel and oxidant at superatmospheric pressure. A duct is provided for regulating the flow of oxidant to the combustion chamber at a plurality of points. Oxidant is guided around the discharge nozzle in such manner as to exert a heat shielding action.

This invention relates to methods and apparatus for burning quantities of fuel and oxidant under pressure in a confined space to provide a flame jet and, more partlcularly, the invention is concerned with a burner con- 'struction in which novel duct arrangements are provided for conducting flows of gases into and out of a burner structure.

It is a chief object of the invention to provide improved methods and means for burning fuel and oxidant at superatmospheric pressure to provide a flame jet.

Another object of the invention is to provide a burner having a novel duct arrangement for regulating or metering flow of oxidant such as air into the burner combustion chamber at a plurality of points.

Still another object of the invention is to provide a burner construction in which a flow of coolant such as air is guided around the discharge nozzle of the burner to exert a desirable heat shielding action.

These and other objects and novel features of this invention will be more fully understood and appreciated from the following description of a preferred embodiment of the invention selected for purposes of illustration and shown in the accompany drawings, in which:

FIGURE 1 is a cross sectional view of one desirable form of burner construction of the invention;

FIGURE 2 illustrates another form of burner construction; and

FIGURE 3 is a cross sectional view taken on the line 33 of FIGURE 2.

In the structure shown, numeral 2 denotes a flame jet burner consisting of a cylindrical member having at one end an inlet 4 through which a mixture of fuel and oxidant is delivered from a mixing chamber 6. Conduit 8 denotes a fuel pipe and 10 refers to an inlet pipe for an oxidant such as air. The two separate flows of air and fuel under pressure move into the mixing space 6 and become thoroughly mixed and discharged into the combustion chamber 14 of the burner in the manner suggested by the arrows.

In accordance with the invention, we provide means for conducting a portion of the air from annular space 12 along a passageway 16 which is comprised by an outer cylindrical sleeve 18 fitted in spaced relation to the outer peripheral surface of the burner 2. The air moves through a passageway as 20 in the direction indicated by the arrows.

At the opposite end of the burner structure there is provided an exit nozzle 22 having a discharge opening 2211 through which is discharged a stream of products of combustion from the combustion chamber 14. The exit nozzle member, in one preferred form, is fitted with a flange portion which is secured around the end of the tubular burner member 2 as shown and this flange portion is further formed with passageways as 24 communicating with a space 26 in turn connecting with the passageway 16. By means of this arrangement air travelling through the passageway 16 is caused to move in a reversely directed manner through the passageways 24 into the end of the burner closely adjacent to the nozzle.

The outer section of the exit nozzle 22 is fitted into the cylindrical sleeve 18 to provide a closely held end wall 30. Through this end wall 30 are formed openings 32 which extend axially and then radially outward to define a flange nozzle part 34. The passageways 32 and flange part 34 serve to conduct a flow of air from the passageway 16 outwardly of the nozzle and in a manner such that the flow of air is caused to move against the flange part 34 and become deflected in a right angularly directed manner.

An important feature of the structure described is a novel heat shielding action. The right angularly directed flow of air outwardly around the flange part 34 of the nozzle operates to provide a continuous heat shielding stream of gases especially effective for protecting the exposed outer parts of the exit nozzle of the burner when a contiinuous jet flame cutting operation is being carried out in a hole or other confined space in a mineral body.

It is pointed out that the flame jet nozzle thus employed is necessarily held in close proximity to a surface which is being cut or spalled and must be advanced from time to time. In the case of cutting a hole the inner extremity of the burner is confined in a small space and becomes exposed to very high temperatures with little opportunity for heat dissipation to rock surfaces. These conditions may produce rapid deterioration of the burner nozzle. By the shielding action described a substantial protection from excessive heating is realized.

In FIGURES 2 and 3 a modified form of air duct means is shown. In this modification numeral 4(l'refers to a burner having a cylindrical combustion chamber 42 with a fuel and oxidant inlet 44. Separate flows of fuel and air for example are supplied through pipes 46 and 48 respectively. At its opposite end the burner 40 is closed by an exit nozzle 50 having a discharge outlet 52 which may, if desired, be formed with cooling means 54.

Mounted around the burner 40 is a cylindrical sleeve 56 which engages against a series of rib portions 58 spaced apart to define a plurality of grooves 60. As will be apparent from an inspection of FIGURE 2 the grooves 60 communicate with a series of openings 53, 55, 57, etc. which allow a flow of gases into the end of the burner adjacent to the nozzle end wall 50. In thus providing the fluted or grooved construction described two desirable results are realized. An improved cooling action is accomplished since the rib portions 58 present relatively large cooling surfaces to provide a high rate of heat transfer. Secondly, it is found that the grooves occurring between the rib 58 may be very effectively employed in a suitable small size or dimension to regulate or control the flow of air so that a desirable metering of air supply used can be realized and thus the efliciency of the burner may be increased for any given type of cutting operation.

The arrangement of the flange 34 and also the grooves and ribs 58 may be modified in various ways within the scope of the appended claims.

We claim:

1. A flame jet burner construction comprising a tubular body which defines a combustion chamber, means for introducing separate flows of fuel and oxidant at one end of the tubular body, an exit nozzle at an opposite end of the tubular body through which may be discharged a stream of products of combustion from the combustion chamber, duct means located around the outer peripheral surface of the tubular body and communicating with the combustion chamber, at points closely adjacent to the exit nozzle, means for supplying an independent flow of oxidant through the duct means to the combustion chamber and passageways formed in the exit nozzle and communicating with. said duct means to provide that a portion of the oxidant supplied to the duct means be discharged through outer peripheral portions of the exit nozzle said passageways formed in the nozzle extending radially of the nozzle throughout a part of the length thereof to provide a heat shielding flow of gases.

2. A flame jet burner construction comprising a tubular body which defines a combustion chamber, means for introducing separate flows of fuel and oxidant at one end of the tubular body, an exit nozzle at an opposite end of the tubular body through which may be discharged a stream of products of combustion from the combustion chamber, duct means located around the outer peripheral surface of the tubular body and communicating with the combustion chamber, at points closely adjacent to the exit nozzle, means for supplying an independent flow of oxidant through the duct means to the combustion chamber and passageways formed in the exit nozzle and communicating with said duct means to provide that a portion of the oxidant supplied to the duct means be discharged through outer peripheral portions of the exit nozzle said exit nozzle is being formed with an outer circumferentially extending battle portion said passageways conducting a portion of the oxidant supplied through the duct means to be directed against the said circumferentially extending bafile.

3. A flame jet burner construction comprising a tubular body which defines a combustion chamber, means for introducing flows of fuel and oxidant at one end of the tubular body, an exit nozzle at an opposite end of the tubular member through which may be discharged a stream of products of combustion from the combustion chamber, duct means located around the outer peripheral portion of the tubular to define a multiplicity of circumferentially spaced apart passageways which extend from end to end of the tubular body and which communicate with the combustion chamber at points closely adjacent to the exit nozzle and means for supplying an independent fiow of gas through the passageways.

4. A structure according to claim 3 in which the independent flow of gas consists of compressed air and the circumferentially spaced apart passageways are formed of a size sufiiciently limited in magnitude to provide for a predetermined metered flow of the compressed air chosen with reference to the volume of the said combustion chamber.

5. A flame jet burner construction comprising a tubular body which defines a combustion chamber, means for introducing separate flows of fuel and oxidant at one end of the tubular body, an exit nozzle at an opposite end of the tubular body through which may be discharged a stream of products of combustion from the combustion chamber, duct means located around the outer peripheral surface of the tubular body and communicating with the combustion chamber, at points closely adjacent to the exit nozzle, means for supplying an independent flow of oxidant through the duct means to the combustion chamber and passageways formed in the exit nozzle and communicating with said duct means to provide that a portion of the oxidant supplied to the duct means be discharged through outer peripheral portions of the exit nozzle said duct means includes a plurality of grooves formed in the outer peripheral surface of the tubular body and an enclosure element mounted therearound.

6. A burner construction comprising a tubular body which defines a combustion chamber having a combustion chamber formed therein, said tubular body including inlet means at one end thereof for introducing flows of fuels and oxidant, an exit nozzle formed at an opposite end of the tubular body through which may be discharged a stream of products of combustion from the combustion chamber, means for circulating a flow of air around the outer peripheral surface of the tubular body, said means including a plurality of spaced ribs formed along the outer periphery of the tubular body in an axially extending manner and a cylindrical enclosure element fitted around the ribs of the tubular body to define a plurality of circumferentially spaced metering passageways through which controlled amounts of air may be conducted into the combustion chamber at points adjacent to the said exit nozzle.

References Cited UNITED STATES PATENTS 2,673,726 3/1954 Oldenkamp 158-4 2,725,929 12/ 1955 Massier 15873 2,734,560 2/1956 Harris et al. 158--4 3,224,486 12/1965 Geller et al. 158-4 3,298,418 1/1967 Briggs 15876 FREDERICK L. MATTESON, 1a., Primary Examiner.

E. G. FAVORS, Assistant Examiner. 

